1. Field of the Invention
The present invention relates to a method for processing of location registration and, more particularly, to a method for processing the location registration of a mobile station using the connection-oriented method of TSB-80, a standard of an application interface between a base station controller (BSC) and a mobile switching center (MSC).
2. Description of the Related Art
PCS (Personal Communication Services) and CDMA (Code Division Multiple Access) systems comprise a number of BTSs (Base Station Transceiver Subsystems) which provide services to Mobile Stations, BSC (Base Station Controller), BSM (Base Station Management System) which manage a number of BSCs, MSC (Mobile Switching Center), and LR (Location Register) system.
In a mobile telecommunication system, the MSC system and other systems are, in general, called BSS (Base Station Subsystem). The BSS includes the BSM, BSC and BTS, in order of precedence.
The main processor of the BSC is called Call Control Processor (hereinafter it is abbreviated as CCP) and the main processor of the BTS is called BTS Control Processor (hereinafter it is abbreviated as BCP).
The conventional location register system is managed in such a connectionless method with serving a call control block within the CCP as a core block.
However since an application interface standard between the base station controller (BSC) and the Mobile Switching Center (MSC) was introduced, the application interface block such as call control block has been managed with the connection-oriented-method, which is suggested in the standard. As a result of that, a method for processing of location registration, which is different from the prior method, has been necessary.
FIG. 1 illustrates the prior art method for processing of location registration in a Personal Communication Services (PCS) system. As illustrated, the method includes a step 110 of transmitting a registration message to the BCP by mobile station; a step 120 of transmitting a registration message to the CCP by the BCP; a step 130 of transmitting a location update request message to the MSC by the CCP; a step 140 of transmitting a location update accept message to the CCP by the MSC; a step 150 of transmitting a registration accept order message to the BCP by the CCP; and a step 160 of transmitting a registration accept order message to the mobile station by the BCP.
The mobile station transmits the registration message to the BCP to request the location registration in step 110, then the BCP generates a location update request message and transmits it to the CCP in step 120. In step 130, the CCP transmits a location update request message to the MSC.
In step 140, the mobile switching center (MSC) registers the current location of the mobile station and then transmits the location update accept message to the CCP. In step 150, the CCP transmits the location accept order to the BCP. After that, in step 160, the BCP transmits a registration accept order to mobile station to inform the mobile station of the result of processing of location registration.
Through the above steps, the mobile switching center recognizes and registers the location of the mobile station.
In the prior art steps for processing of location registration, the CCP, a processor of the base station controller, transmits and receives messages, which includes a parameter of the address for the BTS (BCP) that has transmitted a location update request message, with the mobile switching center, so the CCP can transmit a response to the BCP that requests a location registration.
In order to respond to the BCP that requests a location registration, by using the non-connection method, as stated above, it is necessary to transmit a location registration information message including BCP address, registration type, etc., as location registration information.
If the location registration process is performed as explained above, in the case where a CCP operates, connected with the MSC of another system that does not use the above parameter, it is highly likely that a problem will result because the MSC of the other system cannot analyze the corresponding message.
However if the added parameter for the BCP address is simply deleted to solve the above problem, the mobile switching center transmits signals in a broadcasting manner that scatters signals over all BCPs. Then, the number of unnecessary messages is increased, so a problem occurs in that the system load is increased. To attempt to solve the problem, the location registration is processed in a connection-oriented method by using an application interface standard.
FIG. 2 illustrates a method for processing of location registration in case of using application interface standard (TSB-80) between BSC and MSC. As illustrated, the method includes the steps of: transmitting a registration message to a base transceiver subsystem control processor (BCP) by a mobile station (step 210); transmitting a registration message to the CCP by the BCP (step 220); transmitting a location update request signal to the MSC by the CCP (step 230); transmitting a location update accept signal to the CCP by the MSC (step 240); transmitting a registration accept order to the BCP by the CCP (step 250); transmitting a registration accept order to the mobile station by the BCP (step 260); transmitting a SCCP RLSD (Release) request message to the CCP by the MSC (step 270); and transmitting SCCP RLC (Release Complete) to the MSC by the CCP (step 280).
The processing of signals rather than information, as stated above, is performed in a signaling connection control part (hereinafter it is abbreviated as SCCP) of the CCP. The SCCP plays a role in establishing a node for signal processing and the connection for signal processing is called a SCCP connection.
The detailed description for the operation of FIG. 2 is as follows:
In step 220, the CCP receives a registration message from the mobile station through the BCP. In step 230, the CCP generates a location update request message including the address of the BCP which transmitted the message. The location update request message is transmitted to the MSC through a Complete Network Layer Information Message, which is used to transmit information between network layers on application interface standard. Then the CCP sets a timer for the connection with MSC (step 290).
The Complete Network Layer Information Message is located within the user data field of SCCP connection request and transmitted from the CCP to the MSC. The message includes a connection management request message, a paging response or a location registration message, etc.
In step 240, the MSC transmits a location update accept message to the CCP so as to inform the corresponding BCP that the location registration request has been processed. If the location registration request is refused, the MSC transmits a location update refuse message to the CCP.
The location update accept message (or location update refuse message) can be included in the SCCP connection confirmed primitive, which indicates SCCP connection status, or included in the SCCP connection refused primitive.
The CCP, which has received the location update accept message, stops a timer for the corresponding connection and in step 250, the CCP transmits registration accept order (if failed, location refused order) to the mobile station through the BCP so as to inform that the location registration has been successfully processed.
If the SCCP connection is disconnected, in step 270, the MSC disconnects the connection in such a way that the MSC transmits to the base station a SCCP RLSD message, which is used in the application interface standard as a procedure of SCCP connection release.
In step 280, the CCP releases the SCCP connection and transmits the SCCP RLC message to the MSC for the response to the SCCP RLSD message.
In step 240, if the MSC has used SCCP connection refused primitive, the step of SCCP RLSD 270 and the step of SCCP RLC 280 are omitted because the SCCP connection has already been refused in the MSC.
If the application interface, as described above is used, a signal for processing of location registration, which is transmitted from the mobile station, should be transmitted to the MSC through the BCP call control block, the CCP call control block and the CCP protocol control block.
Therefore, since the steps for transmitting messages become so numerous, the procedure for processing becomes complicated. In addition, if the above referenced method is used, the number of required messages becomes too numerous. As a result, the system performance is decreased.
U.S. Pat. No. 5,479,481 to Koivunen discloses the prior art concerning this field. The Koivunen patent discloses a method for updating subscriber data in a cellular radio system. In the Koivunen patent, a visitor location register (VLR) receives, from a home location register (HLR) of the cellular radio system, a restart indication and changes the restart number (HLR Reset Num). When the visitor location register (VLR) receives, from a mobile exchange, an indication of the establishment of a radio connection with a subscriber, the visitor location register compares the subscriber-specific restart number of the subscriber with the home location register restart number (HLR Reset Num) of the subscriber, and updates the location data of the subscriber on the basis of the comparison.
The Koivunen patent discloses an improved method for updating subscriber data in a cellular radio system having home location register (HLR) and visitor location register (VLR). However, the Koivunen patent does not disclose a method for processing of location registration in a base station (BS). That is, the location registration is a communication between HLR/VLR and MS, and BS (BSC and BTS) intermediately performs only transmitting messages, so a processing method of the BS has been needed.